From d531ebcb57de61bad0ac2e4231280d41d8db4404 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Tue, 22 Mar 2016 18:02:36 +0000
Subject: [PATCH] Key StateHandler._state_cache off of state groups

---
 synapse/state.py | 61 +++++++++++++++++-------------------------------
 1 file changed, 21 insertions(+), 40 deletions(-)

diff --git a/synapse/state.py b/synapse/state.py
index 9d90a437d..14c043001 100644
--- a/synapse/state.py
+++ b/synapse/state.py
@@ -90,18 +90,8 @@ class StateHandler(object):
         """
         event_ids = yield self.store.get_latest_event_ids_in_room(room_id)
 
-        cache = None
-        if self._state_cache is not None:
-            cache = self._state_cache.get(frozenset(event_ids), None)
-
-        if cache:
-            cache.ts = self.clock.time_msec()
-
-            event_dict = yield self.store.get_events(cache.state.values())
-            state = {(e.type, e.state_key): e for e in event_dict.values()}
-        else:
-            res = yield self.resolve_state_groups(room_id, event_ids)
-            state = res[1]
+        res = yield self.resolve_state_groups(room_id, event_ids)
+        state = res[1]
 
         if event_type:
             defer.returnValue(state.get((event_type, state_key)))
@@ -193,24 +183,6 @@ class StateHandler(object):
         """
         logger.debug("resolve_state_groups event_ids %s", event_ids)
 
-        if self._state_cache is not None:
-            cache = self._state_cache.get(frozenset(event_ids), None)
-            if cache and cache.state_group:
-                cache.ts = self.clock.time_msec()
-
-                event_dict = yield self.store.get_events(cache.state.values())
-                state = {(e.type, e.state_key): e for e in event_dict.values()}
-
-                prev_state = state.get((event_type, state_key), None)
-                if prev_state:
-                    prev_state = prev_state.event_id
-                    prev_states = [prev_state]
-                else:
-                    prev_states = []
-                defer.returnValue(
-                    (cache.state_group, state, prev_states)
-                )
-
         state_groups = yield self.store.get_state_groups(
             room_id, event_ids
         )
@@ -220,7 +192,7 @@ class StateHandler(object):
             state_groups.keys()
         )
 
-        group_names = set(state_groups.keys())
+        group_names = frozenset(state_groups.keys())
         if len(group_names) == 1:
             name, state_list = state_groups.items().pop()
             state = {
@@ -234,16 +206,25 @@ class StateHandler(object):
             else:
                 prev_states = []
 
-            if self._state_cache is not None:
-                cache = _StateCacheEntry(
-                    state={key: event.event_id for key, event in state.items()},
-                    state_group=name,
-                    ts=self.clock.time_msec()
-                )
+            defer.returnValue((name, state, prev_states))
+
+        if self._state_cache is not None:
+            cache = self._state_cache.get(group_names, None)
+            if cache and cache.state_group:
+                cache.ts = self.clock.time_msec()
 
-                self._state_cache[frozenset(event_ids)] = cache
+                event_dict = yield self.store.get_events(cache.state.values())
+                state = {(e.type, e.state_key): e for e in event_dict.values()}
 
-            defer.returnValue((name, state, prev_states))
+                prev_state = state.get((event_type, state_key), None)
+                if prev_state:
+                    prev_state = prev_state.event_id
+                    prev_states = [prev_state]
+                else:
+                    prev_states = []
+                defer.returnValue(
+                    (cache.state_group, state, prev_states)
+                )
 
         new_state, prev_states = self._resolve_events(
             state_groups.values(), event_type, state_key
@@ -256,7 +237,7 @@ class StateHandler(object):
                 ts=self.clock.time_msec()
             )
 
-            self._state_cache[frozenset(event_ids)] = cache
+            self._state_cache[group_names] = cache
 
         defer.returnValue((None, new_state, prev_states))